There is no side effect of infusion of nutritional solution for small-sized fetus. If the ultrasound suggests that the fetus is small, and the fetal biparietal diameter and femur length are smaller than the actual gestational week for more than 2 weeks, it may be intrauterine growth retardation, which requires hospitalization for observation, and the infusion of nutritional solution for symptomatic supportive treatment, such as amino acids, to replenish the nutrients needed for fetal growth and development, which generally has no side effects. After the infusion of nutrient solution, most of the fetus is well absorbed and its growth and development speed up. If the fetus is not well absorbed, most of the nutrient solution is absorbed by the pregnant woman, and the growth and development will be slower. If the fetus is small, it is recommended to consider whether or not to supplement the nutrition with nutrient infusion, taking into account the guiding opinions of professional obstetricians and gynecologists. At the same time, should strengthen the pregnant woman’s diet, pay attention to nutritional matching, dietary structure should be reasonable, to ensure that the nutritional intake of pregnancy, eat more food containing high-quality protein and rich in vitamins.